Display the User Box screen.
For details on how to display the screen, refer to Here.
Tap [System] - [Memory RX].
Enter the password, and tap [OK].
Select a fax to print, and tap [Print].
You can also long-tap the target file to display the menu icon, then drag and drop it to to get the same result.
To execute this print job, tap [Yes].
When you print a fax, it is deleted from the Memory RX User Box automatically.